The Next Best Thing
by WilderCapall
Summary: Seijuurou got in a fight with Kou and ended up with Rin. Even though Rin is a huge pain, and they fight constantly. Especially in bed. Seirin, mostly PWP. Possible continuation.
1. Chapter 1

**Summary:** Seijuurou got in a fight with Kou and ended up with Rin. Even though Rin is a bastard and a half, and they fight _constantly._ Especially in bed.

**Disclaimer:**Wilder still doesn't own Free!/Rin/Seijuurou/a life.

**The Next Best Thing**

"Will you_ stop_ pretending I'm my sister?" Rin snarls, but it's not very intimidating, considering that he _is_ naked on his knees and elbows with his ass in the air. "The fact that she ditched you because your dick isn't as impressive as your biceps does _not_ mean you can – " His tirade is cut off by a wordless moan as his captain's fingers curl inside him, and he hides his face in the pillow.

"I am not pretending that you are your sister. I was nice to your sister. And oh _really_, is that why she and I didn't work out?" Seijuurou asks, raising an eyebrow. "Funny, I haven't heard _you_ complaining."

Well. Rin _does_ have a tendency to complain. But not about that.

Rin's answering growl turns into a low whine in his throat, and one hand twists into the sheets while the other moves toward his own cock. Seijuurou swats the hand away and shakes his head.

"_I_ decide when you come."

Rin kicks him in the head.

Seijuurou retrieves Rin's belt from the side of the bed and tightens it around his wrists behind his back before shoving his fingers roughly back in.

"Bitch," Rin mutters. He has to bite the sheets to resist moaning when Seijuurou's free hand comes down on his ass in a sharp slap. And now he's going to have to buy new sheets or learn to sew.

"What was that?"

"I called you a _bitch_," Rin snaps, trying to pull free of the belt so he can punch Seijuurou in the face. He only succeeds in making Seijuurou laugh and thrust his fingers in deeper. "Fuck you," Rin groans, but he wants it.

No matter how much he would love to break a couple of Seijuurou's teeth, he's pretty all right with the fact that they fuck. Even if Seijuurou probably does wish that it was Rin's sister instead of Rin himself.

"No, I'm pretty sure you're the bitch here," the captain chuckles. "Now, I'm pretty sure you want me to fuck you, but you're going to have to ask nicely. Capable?"

Rin turns his head to glare at Seijuurou, who smiles broadly back.

"Or maybe I'll just play with you until you come, hm? Would you prefer that?"

"… No," Rin says, and he shudders when Seijuurou smacks him again, harder this time.

"What do you want?"

Currently, Rin is extremely pissed off and what he _wants_ is to kick Seijuurou in the gut, wriggle out of the goddamn belt, and finish himself off. But if he tries to kick Seijuurou, his current lack of arm support will cause him to tip over and probably fall off the bed, and Rin is not a fan of being laughed at.

"… I want you," Rin growls, frustrated as hell and positively _aching_, because obnoxious as Seijuurou is, he's a damn good fuck and Rin is very, very ready.

"I don't believe I know what you mean. Be specific."

"I want you to fuck me." Rin spits the words like they're acid.

"Little more detail, please."

Rin bites his lip and tries to figure out if this bullshit is worth it. If he _does_ say no, let me go, go away, Seijuurou will. He's not a bad guy, really, he just _really_ likes driving Rin crazy. And making him say things that turn his face as red as his hair.

Rin takes a deep breath and wills himself not to blush like a fucking schoolgirl.

"I want your cock," he groans.

"Go on."

_Are you fucking kidding me._

Rin would love to scream at him, punch him in the face, maybe take control and fuck _him_ for once, but those things are not going to happen today and at the moment Rin would like to be fucked already.

His best bet is to sound as passive-aggressive as possible and hope that it keeps the humiliation down.

"How much of a fucking idiot are you that you need this spelled out, Seijuurou?" he hisses. "I want your cock in my ass and I want you to pretend you're good in bed when you fuck me." His strategy does not work. Rin can feel the heat in his face.

"Well now you're just being rude," Seijuurou says.

But he rises on his knees, knocks Rin's long legs apart a little bit, and grabs the bottle of lube to slick his cock, pumping himself to full hardness. He grips Rin's ass, spreading him to give Seijuurou a better view, and presses his cock against Rin's entrance without pushing in just yet. Rin growls with frustration and tries to grind back against Seijuurou, who holds Rin's hips tightly so he can't.

Maddeningly slow, Seijuurou starts to slide his cock into Rin, pausing at every inch until Rin screams at him and he claps a hand over Rin's mouth. Rin bites him hard enough to draw blood as the movement causes Seijuurou to thrust all the way into him without warning.

"Ow! You little – "

"Quit teasing me, you son of a bitch," Rin tries to growl, but it comes out more like a breathless moan.

Seijuurou looks around for a moment, finds Rin's school tie on the bunk ladder, and gags him tightly enough that he shouldn't be able to bite through it.

"For the love of god, _shut up_," he says, and he starts to thrust into Rin, enjoying the muffled moans and panting through the gag. Seijuurou curves over Rin's back, biting his neck and shoulders, marking him because he wants everyone to know that Rin Matsuoka is _his_. Rin's protests are lost in the tie.

And sure, sometimes Seijuurou wishes that he were with Gou instead of Rin, but he could never have been this rough with her, and he and Rin both like it rough.

He fucks Rin hard, pulling Rin's hips against his own with the slap of skin on skin, and Rin's moans aren't muffled very well anymore and Seijuurou's starting to let out his own. Seijuurou is pretty sure that whoever lives next to Rin is getting sick of this, but he _really_ doesn't care.

Rin's body jerks and shudders with every rough thrust, even with Seijuurou's hands on his hips holding him steady, and noises that can only be described as yips are making their way out of him.

Just as he can tell that Rin is about to come, Seijuurou pulls out of him and leaves his cock just barely touching Rin's hole, and a muffled scream comes from Rin's gagged mouth. Seijuurou loosens the tie and slips it over Rin's head.

"Beg for it."

"Seijuurou, fuck me, _please_ let me come," Rin breathes, not even red anymore, not even embarrassed, just wanting.

Seijuurou leans over to whisper in Rin's ear.

"You want me to fuck your ass until you come?"

"_Yes_."

In one smooth motion, Seijuurou thrusts back into Rin, and Rin screams, and it's only another couple of minutes before Rin comes. He would collapse on the bed if Seijuurou wasn't holding up his hips and still in him. Seijuurou slows down a bit, knowing how sensitive Rin is, especially now. Just a few more thrusts and Seijuurou comes deep inside Rin, who moans and shivers, panting. Seijuurou pulls out and lets Rin flop on the bed before collapsing next to him.

Eventually, Rin starts breathing normally and turns his head to look at Seijuurou.

"Do you _mind?_" he asks, and there's insolence back in his voice.

"Do I mind what?"

"Undoing the _belt_."

"Oh."

"Idiot," Rin mutters as Seijuurou loosens the belt and removes it from Rin's wrists.

And then Rin _might_ sit up and punch Seijuurou in the gut.

"Asshole! What the hell was that for?"

"I do not _beg_," Rin hisses.

"I'm pretty sure you do," Seijuurou laughs, and then he has to dodge another fist aimed at his face. He shoves Rin down, pins his wrists above his head, and glares at him. "Can you not? I _will_ put that belt back on, loop it through the ladder, and leave you here for Nitori to find."

Rin struggles for a minute, his face set in a snarl, but Seijuurou is stronger than he is out of the water.

"Let me go," he says.

"Are you going to hit me again?"

"No."

And he doesn't this time. But Seijuurou has failed yet again at fucking the attitude out of Rin Matsuoka. He has started to doubt that that's going to happen.

But _damn_, is it fun to try.

**End**

May be continued, depending on reception.


	2. Chapter 2

**Chapter 2**

It turned out that Rin did not possess the restraint necessary to resist punching Seijuurou in the face the moment his guard dropped, and now Rin's got the belt wrapped twice around his wrists and once around the bunk bed ladder.

And he's still naked.

And he's really, really annoyed.

Seijuurou had _better_ have a black eye.

* * *

Seijuurou does, in fact, have a black eye. Rin's right hook is better – and a hell of a lot faster – than he expected.

He tells the team that Rin is sick, which they know for a fact is bullshit. Rin has come to practice with the flu. And yeah, he almost yakked in the pool and it was disgusting, but the point is that _nothing_ stops that kid from swimming other than the Iwatobi team coming over for joint practice that first time.

A couple of them snicker to each other and speculate that Rin's probably too sore to swim, based on the last time they saw him with red marks all over his neck.

Most of them do not suspect, however, that Rin is currently belted to his bed, muttering obscenities under his breath and cursing Seijuurou to the depths of hell.

* * *

Nitori opens the door with a towel on his head, rubbing his hair dry, and stops dead.

"Um," he says.

"Shut the fucking door," Rin hisses.

Nitori obeys quickly, but he really doesn't know how to respond to this particular situation. So the natural thing to do is to pull his towel down over his eyes.

"Will you stop _hiding_ and get this fucking belt off of me?" Rin snaps.

Nitori squeaks and edges closer to Rin without looking directly at him. Not like he doesn't want to, but he's pretty sure Rin would kill him.

When he's behind Rin and can fumble with the belt buckle, he sees the bites.

"Matsuoka-senpai, what – "

"Do _not_ ask me what happened." _And do_ not _investigate the stuff on the sheets._

Nitori manages to release Rin, who retrieves a towel from under his bed and stalks into the bathroom.

Rin's wrists have wide stripes of red on them from the belt. His hands are all pins and needles, but they should be all right. They're clumsy as hell at the moment, though, and Rin can barely hold a shampoo bottle long enough to lather his hair. He tries to shake some feeling back into them, but ends up whacking his right hand against the soap dish and yelling a couple of choice expletives. Nitori's anxious voice calls from the door to ask if he's okay, and Rin ignores him until Nitori _opens the fucking bathroom door_ and Rin feels justified in threatening to skin him.

Hot water does not help the multitude of bites and hickeys on Rin's neck and shoulders – if anything, they look darker. He steps out of the shower and dries himself off, wincing as he rubs his hips and shoulders. Seijuurou never plays nice, but this time he's just showing off.

* * *

Rin ignores the snickers from his team members, but when one of them insinuates that Rin has only maintained his spot on the team by letting the captain fuck him, Rin feels the intense desire to break his jaw. He resists breaking the guy's jaw.

"You'd better start letting Mikoshiba fuck _you_ then. I'm beating you by five seconds these days," Rin says, brushing his soaked hair out of his face.

He cares a _little_ bit that everyone knows about him and Seijuurou, but when people do piss him off, he retorts rather than retreating. Best defense is a good offense, right? And Rin has a hell of an offense.

* * *

Rin has a free period first this morning, so he's sleeping in and Nitori is gone when he gets the text.

_Get your ass to my room –Seijuurou_

Rin considers ignoring him. But hell, why not. It's not like he's doing anything. And Seijuurou gets pissed off when Rin ignores him. Pissed off Seijuurou is no fun at all.

Rin hauls himself out of bed and bothers to get dressed, because he highly doubts that he will have time to come back here before his first class starts. He heads to Seijuurou's room, which is a single on the floor below Rin's.

He knocks, and the door opens presently.

"What do you want?" Rin asks, yawning.

"On the bed. Hands and knees. Now."

Rin's eyes narrow, and his answering glare could kill most men.

"Make me," he says.

Perhaps not his best choice of words.

Seijuurou doesn't usually kiss him. When he does, it's not really a kiss. Too aggressive, more an attack on his mouth than anything resembling affection. And yeah, Rin could bite Seijuurou's tongue if he felt like it, but that's not really a good idea considering that Seijuurou also has his hand down Rin's pants and a slightly uncomfortable grip on his cock.

"Get. On. The _bed_."

The words are a formality at this point, because he's just shoved Rin away from him and toward the bed. Rin just sits on the edge, grinning insolently.

"I told you hands and knees."

"I told you to make me."

Seijuurou is so not in the mood for Rin's bullshit today. He pins the younger swimmer and pulls Rin's collar down to bite his neck. Rin squirms a little bit and gasps, because Seijuurou's teeth aren't sharp like his, but he can make it hurt when he wants to.

Rin is extremely sensitive, and unfortunately, Seijuurou has known that since about five minutes into this little whatever-it-is. He can turn Rin into an absolute mess with a flick of his tongue at Rin's hipbone. He doesn't this time, just traces the line of it with his thumb, but even that makes Rin arch his back and bite his lip to stifle noise.

"Fuck you!" Rin snaps as Seijuurou flips him over and lifts his hips so he's on his knees. He groans when Seijuurou smacks his ass hard.

"No no no, we can't have noise this morning," Seijuurou says lightly. "And I don't want you ruining my sheets with those teeth of yours." Rin hears Seijuurou rummaging through his bedside drawer, and suddenly there's a hard rubber bar in his mouth and he can feel Seijuurou tightening a buckle behind his head.

_Well. I _could_ kick him in the face._

But honestly, Rin's a little curious. It seems that Seijuurou is feeling especially dominant today, and that can be fun. This gag is new though.

Rin hisses as Seijuurou belts his hands behind his back again. He attempts to yell "Cut that out, my wrists hurt like a bitch from yesterday", but it comes out as a series of muffled and unidentifiable noises.

"That's better," Seijuurou says, squeezing Rin's ass. He chuckles and pulls Rin's pants down around his knees.

Rin has to wonder what Seijuurou is planning. For one thing, Rin's usually not wearing clothes at this point, let alone shoes. At the moment, his school jacket and shirt are hiked halfway up his back, and Seijuurou is running his fingers along Rin's spine. He reaches the base and keeps going, rubbing the knuckle of his middle finger against Rin's entrance. Rin moans through the gag and twitches a little bit at the sensation.

Rin's thinking he might never get used to the fact that lube is really cold and Seijuurou never bothers letting it warm up before pushing his fingers in. He starts off with two, and Rin inhales sharply. It doesn't _hurt_ much, but it surprises him. What surprises him more is that he doesn't get a third, and Seijuurou's fingers leave him.

Something harder, smooth and cold – metal, maybe? – presses against Rin's ass, and he tries to turn around to get a look at what the hell Seijuurou is doing, but he can't. Whatever it is slides in, and Seijuurou's fingers push it deeper. There's a string or a cord or something attached to it. Rin tenses. And then the thing inside of him starts buzzing, and Rin's back arches and his eyes squeeze shut and he bites down on the gag as hard as he can, because _fuck_.

"So you _like_ that," Seijuurou muses, his fingers still playing with Rin, pressing the toy deeper and then almost pulling it out, and then he pushes it hard against the perfect spot and Rin is shaking so hard he can barely breathe. "Oh yeah, I think you do."

He turns up the dial, and Rin's eyes are rolling back in his head and there's a whimper in his throat. And yes, he's a little humiliated and a little pissed off at Seijuurou's tone. But god_damn_.

"Now, I've got an order for you," Seijuurou murmurs, leaning over the curve of Rin's back to nip at his neck. "Well, more of a bet. I'm going to bet you that you can't keep that in until practice tonight without touching yourself or taking it out." He knows that if he makes it an order, Rin will deck him the moment Seijuurou lets him up. He might do it. But he'll definitely punch Seijuurou first.

The captain turns down the dial a bit and unbuckles the gag, taking it out of Rin's mouth and inspecting the tooth marks.

"Damn. I guess I need something stronger for you."

Rin can't even speak for a minute or so. He's panting, moaning low in his throat and trying to be quiet and failing miserably.

"What… do I get… if I win?" he gasps. He doubts that he's going to win, because even with the toy on the lowest setting, he's not sure he can stand, let alone walk normally.

Seijuurou hasn't really thought about that. He probably should have, because Rin really might be stubborn enough to get through the day.

"Well if _I_ win, I think I'll fuck you in the showers and turn up that toy in your ass while I do it," he says with a grin, and Rin is almost intrigued enough by that to forfeit. But Rin is more stubborn than even Seijuurou gives him credit for.

"And?"

Seijuurou sighs.

"And if you win… I don't know, I'll suck your cock or something. You're not going to win, just _look_ at you, you're a mess."

Rin tries to snarl, and it turns into a whine as Seijuurou cranks up the intensity again.

"Turn it down," Rin groans. "People'll fuckin' _hear_ it."

Seijuurou considers turning it _up_ and letting people wonder what that odd buzzing noise is.

"Please, Rin, that's not even half of what this thing does. _I_ can barely hear it," he says, tugging lightly at the cord as he tapes the control to Rin's thigh. Rin bites his lip trying to shut himself up and tastes blood.

"Seijuurou, goddammit – !"

"Shut up or I'll send you to class with the gag on." Seijuurou says, freeing Rin's wrists and delivering an almost affectionate smack to his ass. Rin's breath hitches, and then he mutters something obscene under his breath and tries to get up. It takes a second attempt before he manages to stand long enough to pull up his pants. He hopes that his trembling legs aren't as noticeable as they feel.

Seijuurou watches him go, sitting against the wall with his arms folded behind his head. He wonders if Rin will be able to walk by the time practice comes around.

He guesses that one of the reasons he's so hard on Rin is that he's _trying_ not to think of him in the same context as Gou. The hair makes it difficult. Rin's foul mouth and the occasional fist to Seijuurou's face make it easier.

Seijuurou does miss her. She's sweet, beautiful, a hell of a lot nicer than Rin, and it doesn't hurt that she's a girl and Seijuurou was pretty sure he was straight until a few weeks ago. He still thinks he might be. He sure as hell doesn't _love_ Rin. The fact of Rin being attractive and a good fuck is fact, not a matter of sexual preference.

The first couple of times with Rin, Seijuurou really did pretend that he was with Gou. Then that got really painful. Rin sank his sharp teeth into Seijuurou's hand when the captain tried to play with his hair, and Seijuurou ended up in the school nurse's office pretending he'd been bitten by his sister's dog.

Seijuurou shakes his head and forces himself to his feet. He has class in ten minutes.

* * *

Rin is very inefficient in class today.

All he wants to do is run to the bathroom and get himself off and then he thinks maybe he'd be able to get through the rest of the day. But Rin is determined to prove Seijuurou wrong. He doesn't even care that much about the bet, though the image in his head of the captain's mouth on his cock isn't bad.

Between the toy, people asking him if he's sick because his face is red, and cursing Seijuurou (he's been doing a lot of that lately), Rin actually doesn't manage to fall asleep in class like he usually does. He gets approximately the same amount of work done, though. Exactly what is the point of maintaining a higher grade than is necessary to stay on the swim team?

Around lunchtime, though, Rin stops caring about proving Seijuurou wrong.

He's in a stall, one hand wrapped around his cock, breathing hard. And then he hears the door open just as he's about to come, and he freezes.

"You do realize you're really loud, right?" Seijuurou asks casually.

"Yeah, yeah, I lose, fuck you," Rin growls, zipping up his pants and stepping out.

"I'm pretty sure you don't want to go back to class with that," Seijuurou says, gesturing to the front of Rin's pants.

Rin sighs and shakes his head.

"Let's see," Seijuurou begins, "I _could_ fuck you in here, let you come, see if you can make it through the rest of the day. Or I can leave you here to finish yourself off. Either way you lose and I'm going to fuck you in the showers later."

Rin lets a long breath hiss through his teeth.

"I don't have a gag. You have to shut the fuck up if we're doing it in here," Seijuurou says.

"I can do that," Rin says through clenched teeth.

Seijuurou pins him against the granite counter where the sinks are set, bent over in front of one of the mirrors. Rin decides that he'd rather look at his hands, and Seijuurou grabs his hair and makes him look up.

"I want you to watch me fuck you. You make some pretty faces." He undoes Rin's pants and yanks them down, pulling a tube out of his pocket with his other hand. Before putting his fingers in, though, he runs a hand down Rin's inner thigh and turns the dial up. Rin trembles and bites his lip, gripping the sink hard.

As it turns out, Seijuurou isn't bothering with fingers today. Rin gasps as he feels Seijuurou's cock press against his entrance and start to slide in, stretching him around its length until it touches the vibrator and Rin would love to scream but he doesn't.

"Fuck, Rin, that feels good," Seijuurou mutters. "And you're so tight like this."

"You didn't fuckin' prep me, bastard, of course I'm goddamn tight," Rin hisses, and Seijuurou smacks his ass.

"Quiet," he says, and he starts to move, hitting the toy with every stroke until Rin can't control a couple of quiet moans. He _really_ doesn't want anyone to come in and see this.

After Rin comes, a low whine issuing from his throat, Seijuurou pulls out and says he doesn't want to get the toy all dirty just yet. He tells Rin to go to class. Luckily for Rin's sake, Seijuurou does turn down the dial a bit.

* * *

Practice. Rin's legs are still trembling slightly when Seijuurou corners him in the locker room and pulls out the toy, leaving it on while he does it and only turning it off after it's out.

Rin isn't nearly as fast as he usually is, but he still manages to win his time trials in freestyle and fly.

After most of the team has showered and left, Seijuurou pins Rin against the shower wall and hands him the toy.

"I want you to get yourself ready and put that in. And then I'm going to turn it on and fuck you against the wall. Got it?"

Rin nods and closes his eyes as he works a couple of fingers into himself, stretching enough that it doesn't hurt to push the toy inside. Seijuurou looks satisfied, and he grabs Rin's hips and shoves his cock in quicker than Rin was expecting.

"Fuck!" Rin kind of yelps, and that's kind of embarrassing, which is weird because he's not really embarrassed that he's got Seijuurou's cock and a vibrator in his ass.

Then Seijuurou cranks up the dial, from nothing to almost the top setting, and Rin lets out a little scream and it echoes a bit. Seijuurou twists his fingers into Rin's hair, pushing his head against the wall as he starts to thrust, harder than earlier, stronger, pushing the toy deeper with every movement, and _he's_ moaning now, one hand on Rin's hip and one on the control, playing with the setting. Any kind of attitude from Rin is gone for the moment – he's breathing hard, mouth open, back arched, moaning like a whore and begging "please, more, harder".

Seijuurou actually comes first, the combination of Rin's tightness and the vibration of the toy driving him over the edge. Rin's not far behind once Seijuurou's hand starts pumping his cock.

Rin, as always, takes a few minutes to get his "raging asshole" behavior back. Seijuurou finds that he's not really disappointed when it surfaces. He doesn't want to break Rin, exactly.

He's okay with spirit.

**End Chapter**

Um. So this is what happens when I let myself write kink.


End file.
